When looking at PCIe NIC based systems performance can be assessed using the ODP PCIe optimised implementation (odp-dpdk, or the generic reference implementation odp-linux can be used, this implementation is not optimised for a specific platform.
Some representative numbers that use the OpenFastPath TCP stack and the fpm_burstmode test are shown here for a 40Gbps NIC.
with odp-dpdk scaling can be seen to be quite liner out to twelve cores
with the odp-linux reference implementation scaling is again good with a lower overall throughput
The full results